降低发电煤耗 增加燃煤发电量

我国在今后相当一段时间内燃煤发电仍将占有主力地位,为了达到降低发电煤耗,实现用现有的煤多发电的目标,需要对现有燃煤电厂进行改造。首先,利用已掌握的技术改造现有电厂和建设新电厂,如缩短主蒸汽管道长度、提高二次过热温度、加强管道和阀门保温、用冷凝水冷却发电机、采用可调节气封、取较深处的海水作为电厂冷却水、降低锅炉排烟温度等;其次,利用最新技术就地改造20×104kW、10×104kW及12.5×104kW机组,就地改造投资少,不用再征地,生产辅助设备基本可用原有设施,节约的煤炭费用6年就能收回投资;第三,发展更高效的发电机组,提高蒸汽参数,特别是将蒸汽温度提高到700℃,可以把电厂的净效率提高到56%,煤耗可降至210g标煤/(kW.h),关键是研究开发一种新的耐高温的钢材,如果此项技术难题被解决,火电厂可减少1/3的燃煤量,大大降低二氧化碳排放量;第四,国家应大力改造工业锅炉,发展热电联产,利用供热来降低发电能耗。

Reducing Coal Consumption in Power Generation,Increasing Coal-based Power Production

China will still rely on coal to meet its electricity demand in the foreseeable future.In order to reduce coal consumption in power generation and generate more power using the currently available coal deposits,China needs to upgrade its existing coal-fired power plants.Firstly,China should equip its existing and future power plants with currently available techniques,such as shortening the length of the main steam pipe,raising secondary overheating temperature,strengthening insulation for pipes and valves,using condensed water to cool down generators,introducing adjustable air seal,using deep seawater as cooling water for the power plant and reducing the temperature of exhaust from boilers.Secondly,the country should use the latest technology to upgrade its 20×104kW,10×104kW and 12.5×104kW generators.Onsite upgrading requires low investment and eliminates the need for land acquisition.Most existing ancillary facilities can continue to work and investment can be recovered within six years by means of coal savings.Thirdly,China should develop more efficient generators and raise steam parameters.Particularly,when the temperature of steam is raised to 700℃,the power plant’s net efficiency could rise to up to 56% and coal consumption could drop to 210g of coal equivalent/kW·h.The key in this effort is to develop a new type of heat-resisting steel product.Once this challenge is overcome,a coal-fired power plant’s coal consumption could drop by one third and carbon dioxide emissions would also drop significantly.Lastly,China should step up the upgrading of industrial boilers and develop integrated heat and power production to utilize heat supply to reduce energy consumption in power generation.